Inconel 600
Suitable for severely corrosive atmospheres.
Good resistance to oxidisation.
Do not use in sulphur bearing atmospheres.

1100°C

800

Incoloy 800
Suitable for severely corrosive atmospheres.
Good resistance to oxidisation and carburisation.
Suitable for use in sulphur bearing atmospheres.

1100°C

446

AISI 446
Suitable for severely corrosive atmospheres.
Suited for use in high concentration sulphur bearing atmospheres. at high temperatures.
Mount vertically above 700ºC.

1150ºC

Specialized Sheath Materials

114

Nicrotherm DTM
For high temperature Type K and almost all Type N applications.
Very good high temperature strength.
Excellent in oxidising, carburising, reducing and vacuum atmospheres.
Don not use in sulphur nearing atmospheres.

MA253
An austenitic chromium-nickel steel alloyed with nitrogen and rare earth metals.
High creep strength, very goodresistance to isothermal and cyclic oxidation.

1150°C

6

Secondary SheathMaterials

Max.
Temperature

IAP

Impervious Aluminous PorcelainSuitable for base metal thermocouples.Low temperature coefficient.Suited to kiln applications.Requires support at high temperatures if horizontal.

1400°C

IM

Impervious MulliteFor use with precious metal thermocouplesGreat mechanical strength.Relatively inert to suplhurous and carbonaceous atmospheres. Often used as a secondary sheath with silicone carbide primary.

1600ºC

IRA

Impervious Recrystallised Alumina
For use with precious metal thermocouples.
Fair thermal shcok resistance. High inertness to chemicals.
Ideal for reducing carbonaceous atmospheres.
High resistance to alkaline and other fluxes.

1800°C

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When added protection to the conductors is required,
a secondary closed end ceramic sheath within the primary
metal protection sheath can be specified. This composite
protection sheath will encompass the twin or four bore
insulators and their associated thermocouple elements.